_______Titilsa Hello my name is Sturla and this is my project from - - PDF document

_______Titilsíða Hello my name is Sturla and this is my project from Mechatronic class under instructions from Joseph Timothy Foley. - „Light Sensor Security Safe“ . As the title implies it’s a Security Safe like all other safes but is different in that the locking mechanism takes in a password in the form of light signals, in fact a morse code. I chose this project because it implements most aspects of mechatronics. Combines mechanical and electrical engineering and computer scienceI. That is, building the circuit, programming and building the safe from scratch. ________Backround I estimate that there has been a demand for a secure place to store valuables for as long as we have had personal things and currency. There are records of some kind of locking mechanism from 2000BC and the first patent was issued in Britain in the early 1800. Security safes are sold in all kinds of shape and sizes and have varieties of locking mechanism to choose from ________Why? So why am I building a security safe that open with a light signal when all this variety of safes are on the market? And what is the problem with the ones that you can buy today? As far as I can see there are no safes out there that has a real creative and fun way to open, and certainly no light morse code locking mechanism on the market, and morse is so much

• fun. So the problem I am trying to solve is to make a safe more creative and appealing.

But who really cares about opening safes creatively you may ask. And who would really hide their valuables in an easily broken wooden safe? ________Kids Kids that want to hide something from their siblings. Toy safe that is only for securing things from people that may want to open the safe but would never break it. My solution is therefore better than what is on the market today in regards to my target audience. ________VS kids would rather want my creative and fun safe than this boring one

________Requirements Although the safe is not intended to be thief proof there should be no obvious way to open it without making a mark. The hinges have to be inverted and the safes frame has to be glued and screwed together. There should be no handle on the door to make sure there would never be unnecessary strain and stress to the Servo motor that holds the door locked. Therefore a good spring system has to be in place. It has to be able to work in indoor ambient environments. The user has only 3 tries before the master password is initialized The speaker makes an error noise for wrong input and plays a song when it opens It has a green LED for wrong input and a green one for the right password And when I close the door I make one long signal and it closes, the red LED will be lit until it is safe to let go of the door Now I show you the design process ________Design process I began by designing the safe and used SolidWorks to scetch up the prototype. I used the 3d assembly sketch to make sure that there were no parts that would not fit each

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I then took the technical drawings that you see a sample of here to a workshop where I built it from the ground up. _________Workshop Here are a few photos from the building process, here you can see the front face coming together. I used the table saw to make all sides and then used a jig saw for the door opening. I then drilled the holes for light sensor and LEDs. I then made sure to glue and screw everything together. Because this is a prototype that I would have to be able to open and show the inner workings I made a lid which I milled so it would sit nicely to the top and so that the lid would not be very noticeable.

I fastened the hinges inverted so that there was no easy way un-screwing them. Then I made the circuit with all components _________Circuit and components I sketched up the circuit diagram in the program Altium. I checked the voltage and current limits for all components and chose the right resistors for each so that it would not burn over. _________Programming First I tested each component separately with simple inbuilt programs in the Arduino programming tools. I then made a modular dependency diagram to help me to remind me of the whole picture while programming. I also made a pseudo code that helped me a lot and made the programming relatively easy. There is one part that is crucial and that is the security _________Security Morse light signal has two types of signals, short and long. If someone would make a system that would automatically cycle through all possible light signals on as shortest possible time, how long would it take to crack the safe. It is really not that safe to have only two possible signals to choose from but safe enough for kids at least. It also adds to the security that when someone encounters this safe with no knowledge of how it works, he would never guess it takes in a light signal for password. __________Future work It could have cheaper components and use more easy and productive way to build the frame, and even build it from other materials like plastic or aluminum. If I would order a lot of prebuilt circuits from my design in Altium it would come very cheap I could explore alternatives from Arduino that would perhaps do the same job cheaper. The safe could use more rugged design and better housing for the arduino. I would also like to complicate the signal processing and make it understand fast flashes of lights in specific order, that would take the security of the algorithm to another level.

__________ Finished product Here you can see the finished prototype And to finish the presentation I will show you how it works. Right now I have the short password with the signal S S L and the master-password as the famous SMS Morse code. S S S LL SSS As you can see the all the requirements were met, from the inverted hinges to the master- password. Thank you